The Pentagon Force Protection Agency is taking new steps to "protect those who protect our nation," including a five-year, multimillion-dollar project to upgrade technology, and a separate project to make the Arlington, Va., complex more 'WMD-proof' by installing sensors that can detect biological and chemical weapons.

Images From Pentagon Shooting Scene

"Really, it's a complete reinvention of security here at the Pentagon," said PFPA Director Steven Calvery in an interview with the Associated Press.

More immediate security changes have been put in place since the March 4 shooting outside the Pentagon Metro station, when gunman John Patrick Bedell shot at three PFPA officers before he was killed by their return fire. Now visitors to the Pentagon face more vigorous screening, and random searches have been increased.

Calvery also said there will be improvement to his agency's communications system and command center, and better outdoor lighting. The agency will also continue training officers in active shooter situations, which clearly paid off last month. The officers who took out Bedell had just undergone the training a few days before, according to officials.

Jeffery Amos, an officer who was injured in the March 4 shooting, reported for his first day back on duty today. "Flashes [of the shooting still] run through my mind," he said.

While the shooting and other threats may make his job more challenging, Amos also said it's made others realize just how important his job is.